The present invention relates to an optical rotary adapter and an optical tomographic imaging system using the same and more specifically to an optical rotary adapter that provides rotatable connection between optical fibers for guiding measuring light to the object under measurement and guiding returning light from the object under measurement to acquire an optical tomographic image of the object under measurement and an optical tomographic imaging system that irradiates the object under measurement with light and acquires a tomographic image from the light reflected by and returned from the object under measurement.
Acquisition of a cross-sectional image of a sample under measurement such as biological tissue without cutting thereinto may be achieved using an optical tomographic imaging system employing optical coherence tomography (OCT) measuring.
The OCT measuring is a kind of optical interferometric measurement using the optical interference that occurs only when the optical path lengths of the measuring light and the reference light, into which the light from the light source is divided, are matched to within the coherence length of the light from the light source.
An optical tomographic imaging system using the OCT measuring is disclosed, for example, in JP 2000-131222 A, which comprises a light source; a first optical coupler for splitting the light emitted from the light source into measuring light and reference light; an optical scan probe including a measuring unit for irradiating the sample under test or the object under measurement with the measuring light and detecting the light reflected and returned therefrom, an optical fiber for transmitting the measuring light and the returning light, and a transparent sheath covering the optical fiber and the measuring unit; and a second coupler for causing the reference light to interfere with the returning light both guided along the same optical path length as the measuring light; and an optical tomography system including a computing unit for detecting a tomographic image from the results of interference. With the optical tomographic imaging system disclosed in JP 2000-131222 A, which has the optical fiber in the measuring unit rotatably connected to an optical rotary joint, the measuring unit located close to the tip of the optical scan probe is inserted up to a position to be measured and rotated by turning the optical fiber to acquire a plurality of tomographic images of the object under measurement with its rotating measuring unit, thus reconstructing a two-dimensional sectional image.
In the optical rotary joint disclosed in JP 2000-131222 A, a rotor into which the rotary optical fiber is inserted along its axis is fitted into the socket of a rotor receiver into which the stationary optical fiber is inserted along its axis such that the rotor receiver rotatably supports the rotor by the intermediate of bearings. The rotor is turned at a constant speed via a belt. Convex lenses are disposed on one end of the rotary optical fiber and one end of the stationary optical fiber opposite each other to permit efficient optical transmission between the stationary optical fiber, not rotatable, and the rotary optical fiber, adapted to be rotatable.